You may start SqueezeCenter automatically at startup by adding
the following lines to /etc/rc.local:

if [ -x ${PREFIX}/bin/slimserver.pl ]; then
	${PREFIX}/bin/slimserver.pl --daemon 2>&1 \
	    > /var/log/squeezecenter/startup.log
fi

To stream via HTTP, connect to http://yourhost:9000/stream.mp3
and control the player from SqueezeCenter's usual web interface.

** SQUEEZECENTER IS BY DEFAULT OPEN TO ANYONE ABLE TO CONNECT **

To restrict access, connect to http://localhost:9000/ and go to
Settings/Advanced/Security, where you can restrict by IP address
or password.
